Unverified Commit e8065df5 authored by Sunil V L's avatar Sunil V L Committed by Palmer Dabbelt
Browse files

RISC-V: ACPI: Enhance acpi_os_ioremap with MMIO remapping 



Enhance the acpi_os_ioremap() to support opregions in MMIO space. Also,
have strict checks using EFI memory map to allow remapping the RAM similar
to arm64.

Signed-off-by: default avatarSunil V L <sunilvl@ventanamicro.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: default avatarConor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20231018124007.1306159-2-sunilvl@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 0bb80ecc

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ config RISCV 
	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST

	select ARCH_HAS_UBSAN_SANITIZE_ALL

	select ARCH_HAS_VDSO_DATA

	select ARCH_KEEP_MEMBLOCK if ACPI

	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX

	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT

	select ARCH_STACKWALK

arch/riscv/kernel/acpi.c

+85 −2
Original line number Diff line number Diff line
@@ -14,9 +14,10 @@ 
 */



#include <linux/acpi.h>

#include <linux/efi.h>

#include <linux/io.h>

#include <linux/memblock.h>

#include <linux/pci.h>

#include <linux/efi.h>



int acpi_noirq = 1;		/* skip ACPI IRQ initialization */

int acpi_disabled = 1;
@@ -217,7 +218,89 @@ void __init __acpi_unmap_table(void __iomem *map, unsigned long size) 


void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size)

{

	return (void __iomem *)memremap(phys, size, MEMREMAP_WB);

	efi_memory_desc_t *md, *region = NULL;

	pgprot_t prot;



	if (WARN_ON_ONCE(!efi_enabled(EFI_MEMMAP)))

		return NULL;



	for_each_efi_memory_desc(md) {

		u64 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);



		if (phys < md->phys_addr || phys >= end)

			continue;



		if (phys + size > end) {

			pr_warn(FW_BUG "requested region covers multiple EFI memory regions\n");

			return NULL;

		}

		region = md;

		break;

	}



	/*

	 * It is fine for AML to remap regions that are not represented in the

	 * EFI memory map at all, as it only describes normal memory, and MMIO

	 * regions that require a virtual mapping to make them accessible to

	 * the EFI runtime services.

	 */

	prot = PAGE_KERNEL_IO;

	if (region) {

		switch (region->type) {

		case EFI_LOADER_CODE:

		case EFI_LOADER_DATA:

		case EFI_BOOT_SERVICES_CODE:

		case EFI_BOOT_SERVICES_DATA:

		case EFI_CONVENTIONAL_MEMORY:

		case EFI_PERSISTENT_MEMORY:

			if (memblock_is_map_memory(phys) ||

			    !memblock_is_region_memory(phys, size)) {

				pr_warn(FW_BUG "requested region covers kernel memory\n");

				return NULL;

			}



			/*

			 * Mapping kernel memory is permitted if the region in

			 * question is covered by a single memblock with the

			 * NOMAP attribute set: this enables the use of ACPI

			 * table overrides passed via initramfs.

			 * This particular use case only requires read access.

			 */

			fallthrough;



		case EFI_RUNTIME_SERVICES_CODE:

			/*

			 * This would be unusual, but not problematic per se,

			 * as long as we take care not to create a writable

			 * mapping for executable code.

			 */

			prot = PAGE_KERNEL_RO;

			break;



		case EFI_ACPI_RECLAIM_MEMORY:

			/*

			 * ACPI reclaim memory is used to pass firmware tables

			 * and other data that is intended for consumption by

			 * the OS only, which may decide it wants to reclaim

			 * that memory and use it for something else. We never

			 * do that, but we usually add it to the linear map

			 * anyway, in which case we should use the existing

			 * mapping.

			 */

			if (memblock_is_map_memory(phys))

				return (void __iomem *)__va(phys);

			fallthrough;



		default:

			if (region->attribute & EFI_MEMORY_WB)

				prot = PAGE_KERNEL;

			else if ((region->attribute & EFI_MEMORY_WC) ||

				 (region->attribute & EFI_MEMORY_WT))

				prot = pgprot_writecombine(PAGE_KERNEL);

		}

	}



	return ioremap_prot(phys, size, pgprot_val(prot));

}



#ifdef CONFIG_PCI